Notes I made from going through the Networking on z/OS - Mainframes and networks documentation provided by IBM

A network typically comprises users, software applications, and computers such as mobile phones, desktop computers, laptops, and mainframes, all interconnected to allow for the effective exchange of data and files. Transactions on the network should be as fast and secure as possible.

Networks are categorized into three types: the internet, intranet, and extranet.

• The internet is a global computer network providing a variety of information and communication facilities, consisting of interconnected networks using standardized communication protocols. It allows computers to communicate and share information, such as connecting to Google's servers remotely to search for information stored on their indexed pages.

• An intranet is a network of computers owned and controlled by one institution, and access to information on the network is determined and authorized by that institution.

• An extranet is similar to an intranet but allows users outside of the owner's institution or organization to access information on the network. It is often accessed by business partners, suppliers, and customers to connect and exchange data, and is usually enabled by the world wide web.

Use of networks in high-volume transactions

Networks play a crucial role in handling high-volume transactions in various industries, such as the banking sector. One of the key technologies used in these types of transactions is the mainframe.

Mainframes are specially designed to handle large amounts of data quickly and reliably. They are commonly used in high-volume transactions, such as ATM withdrawals, due to their ability to process multiple transactions simultaneously. This allows for a smooth and efficient experience for the user, as they only experience a delay of a few seconds from the time they enter their PIN until the funds are dispensed.

In the case of an ATM transaction, the mainframe is responsible for communicating with the bank's systems to verify the user's PIN, check their account balance, and process the withdrawal request. This happens in real-time, allowing for a seamless and instantaneous experience for the user.

Security is also a major concern in these transactions, and the mainframe plays a crucial role in providing it. It uses encryption and other techniques to protect sensitive data, such as personal identification numbers (PINs) and account information, from unauthorized access.

Therefore, mainframes are used in high-volume transactions because of their ability to process large amounts of data quickly and securely, making the transactions fast and secure for the users.

The typical advantages of mainframes

• High availability - It is important that networks, such as the one used by an ATM, are always available and operational. This ensures that users can access the services they need when they need them, except in the event of power outages or technical faults. In most cases, the system should have a failover mechanism that can make it operational.

• Security - Mainframe security is a complex topic, but in the context of an ATM transaction, the mainframe ensures that sensitive information, such as a user's PIN, is transmitted in an encrypted format to protect it from unauthorized access.

• Performance and responsiveness - As discussed earlier, ATM transactions are completed in a matter of seconds due to the mainframe's ability to process large amounts of data quickly and efficiently. The system is designed to provide a responsive and fast user experience with minimal delay.

In summary, high availability, security, performance and responsiveness are all crucial considerations in the use of networks in high-volume industry transactions, such as ATM withdrawals. Mainframes are designed to meet these requirements, by providing fast and secure processing, encrypted data transmission and a failover mechanism for high availability.

Role of a network administrator in a large network environment

The role of a network administrator can vary depending on the size of an organization and the technologies in use. Generally, a network administrator is responsible for managing and maintaining the organization's computer networks.

In the case of a z/OS mainframe network, a network administrator must have a thorough understanding of the operating system's communications interfaces to effectively manage the network.

Some specific responsibilities of a z/OS network administrator may include:

• Defining, maintaining, and modifying an existing mainframe network

• Providing technical guidance to application development and business unit projects

• Troubleshooting and resolving network issues

• Optimizing network performance

• Planning for capacity and scalability

• Developing and maintaining procedures for network operation

• Training other network operators

• Keeping up-to-date with emerging network technologies

• Evaluating and implementing new network technologies to improve the network.

In short, a network administrator is responsible for ensuring that the organization's computer networks are secure, efficient, and reliable. This involves constantly monitoring the network, troubleshooting and resolving issues, maintaining network security, and planning for future network needs.

Major components of a z/OS communications server

Network infrastructure refers to the underlying physical and logical structure of a network. It includes the hardware and software components that are used to connect different devices on a local area network (LAN) or a wide area network (WAN).

This infrastructure typically includes equipment such as routers, switches, bridges, and hubs, which are used to route and direct network traffic. These devices are connected to end devices such as computers and servers using various types of cables, such as copper and fiber optic, or wireless technologies like Wi-Fi.

Network infrastructure also includes software and protocols that are used to manage and control network traffic, such as network operating systems, security software, and network management tools. These software components work together with the physical components to ensure that the network is efficient, reliable, and secure.

Network infrastructure refers to the underlying physical and logical connections, devices and protocols that make up a network that allows the devices to communicate with each other, enabling the transfer of data, voice and video packets.

Source: IBM. "Mainframes and Networks." IBM Docs, IBM, accessed January 14, 2023, ibm.com/docs/en/zos-basic-skills?topic=main..